My Dog Is 11 And Diagnosed With Cushings Diease. Haven't

My dog is 11 and diagnosed with Cushings diease. Haven't given her any meds, but she just went to the vet, yesterday. Over the weekend she stopped drinking or eating. Before this, eating and drinking was excessive. They just called that her electrolites are out of whack and her ALP is high.
Last night they hydrated her and she was fine this morning. but by this afternoon, she is listless again. She is going to stay overnight at the vet to see if they can help here. Can you recommend anything?